The U.S. Supreme Court delivered a limited blow to organized labor Monday when it ruled home-care workers who object to union membership cannot be forced to pay union dues.

But the effect could broaden to other litigation in the works.

The court stopped short of reversing decades of precedent that requires many public-sector workers to pay partial dues to unions that negotiate their contracts and provide other services, even if they don’t like the union’s lobbying activity.

Yet Justice Samuel Alito criticized a precedent called Abood v. Detroit Board of Education that gave states the right to compel union dues, suggesting other cases with other facts may have a different outcome.

Organized labor, including National Nurses United, blasted the ruling and said it “continues a dangerous pattern of undermining democracy as well as eroding the rights of workers to have a collective voice through their unions."

Supporters of the ruling, including the Sacramento-based Pacific Legal Foundation, say the Court acknowledged “the elephant in the room:” that a public employee union’s collective bargaining function is indistinguishable from any other lobbying activities.

The decision in Harris v Quinn applies to home health-care workers paid by a state Medicaid program in Illinois. The high court ruled these workers are not “full-fledged employees” because they are hired by individual patients and work in private homes. Because home care workers are not real state employees, they don’t have to pay the so-called union “agency fees,” the court ruled.

This is a blow to Service Employees International Union, which has organized thousands of home care workers in California and other states. But it’s limited to home-care workers.

“We’re still evaluating it,” Christopher Calhoun, a spokesman for SEIU California. “The decision is rooted in some factors that may not be the same in California.”

On another level — particularly in California — the ruling could be “quite significant,” said David Tyra, a labor lawyer at Kronick Moskovitz Tiedemann & Girard in Sacramento who represents management.

There’s a case before the Court of Appeals for the Ninth Circuit in which teachers use the same argument as workers in the Harris case to protest payment of union dues.

“That may be the big takeaway,” Tyra said. “Even though Harris looks limited, the other shoe may be ready to drop.”